Sliding vane rotary compressor



May v17, 1949. c. sHoRRocK 2,470,656

Patented May 17, 1949 UNITED STATES PATENT cFFicE Application July 18, 1946, Serial No. 684,525 In Great Britain July 27, 1945 2 Claims.

The subject matter of this application refers to improvements in the construction of rotary compressors particularly of the eccentric drum type as frequently used for supercharging internal combustion engines.

With certain compressors of this type, the varying relative angular movement of the vanes is made possible by employing trunnion bearings which allow of a semi-rotary or oscillating movement of the trunnions in their housing and a sliding movement of the vanes, which pass through suitable slots in the trunnions themselves.

It is found that the most suitable materials for the vanes (often of steel) to slide in, is by no means ideal for the oscillatory movement in the rotor (generally made of soft light alloy).

In order to provid-e the best combination of suitable materials for the construction of the rotor vanes and trunnions the present invention provides for the use of two different materials between the vane and the rotor, either combining different materials to form the outer running surface and the slot of the trunnion or using a housing in the rotor of material suitable for the oscillation of a trunnion of material adapted for the sliding of the vane-or possibly both cornbined.

In a prior compressor of this kind using a steel blade and a light alloy rotor, I formely used a fibre trunnion which carried the steel blade and oscillated in the light allow rotor; and in practice this was for many years regarded as ideal and much more satisfactory both as regards wear and no undue lubrication requirement than any other arrangement known. I have now, however, discovered after research that surprisingly better results are obtainable in these respects if a second material is appropriately used between the steel vane and the light allow rotor, giving a combination of surfaces for the sliding and the oscillatory movement in which one surface is of hard metal and the other an appropriate nonmetallic wear-resisting material or the light alloy. Accordingly parts of at least two materials are interposed in such a manner as to provide these combinations of surfaces.

In practice, either the slot surfaces of the trunnion, in which the hard steel blade slides,l can be enclosed by a hard steel metal shell to 2 oscillate in the light alloy of the rotor; or a housing of hard metal can be used in the rotor to carry a trunnion made of the same material throughout; or possibly both expedients can be combined, using a trunnion with its slot surfaces and outer surfaces of different materials as well as using a housing fixed in the rotor body. In each case the arrangement is such as to provide the combinations of surfaces set out above.

In the accompanying drawings which illustrate the invention in a diagrammatic manner,

Fig. 1 shows in section one construction of trunnon bearing for a compressor of the kind referred to above,

Fig. 2 shows in section an alternative construction.

Referring rst to Fig. 1, the vane I is mounted on the vane carrier 2 and passes through a trunnion mounted in the rotor 3; the vane can therefore move radially and angularly in relation to the rotor 3 as it moves round in contact with the eccentric casing 4.

The trunnion is formed with a light metallic outer sleeve 5 with a core 6 of light bonded material such as that sold under the trade names of Fabroil and Ferobestos which provides good wearing properties at the Contact with the slot faces. The names Fabroil and Ferobestos refer to phenolic synthetic resin-impregnated fabric or similar material with an asbestos base. These materials constituting the cores 6 provide good wearing properties in their contact with the vanes I.

The core 6 is pressed, moulded or cast into the sleeve 6 which is ground on the outside to give a good bearing with the rotor.

In the modified construction shown in Fig. 2, separate metal trunnion housings 1 are secured in the rotor 3 and receive the trunnion 5.

I claim:

1. A rotary compressor including a soft light alloy rotor, trunnions and flat hard metal varies, wherein said vanes are caused to slide through said trunnions which have an oscillatory motion in the rotor, each trunnion consisting of at least two materials interposed between the vanes and the light alloy of the rotor one of such materials being arranged to give a combination of surfaces selected for its suitability where the sliding motion of said vanes. occurs and the other arranged to give a combination of surfaces selected for its suitability where the oscillatory motion of the trunnion occurs.

2. A rotary compressor according to claim 1, wherein each trunnion consists of two semicylindrical cores each having a shell, and Wherein the cores in sliding Contact with the vanes are made of non-metallic Wear-resisting material, and the shell in oscillatory Contact with the rotor is made of hard metallic material.

CHRISTOPHER SHORROCK.

REFERENCES CITED The iollowingreferences are of record in the le of this patent:

Number Number UNITED STATES PATENTS Name Date Mackenzie Jan. 2, 1855 Nadeniczek Apr. 17, 1894 Fisher Aug. 27, 1895 Rose Aug. 16, 1898 Stern July 9, 1929 Napolitano Feb. 25, 1941 FOREIGN PATENTS Country Date Great Britain July 3, 1919 

